I'm kind of sceptical. Like a lot of people I have a case to protect my phone, this would essentially be a non-starter for a phone with dual display. My solution is a bit different. Make a flip case with an eInk on the cover. Let it connect to the phone through the micro USB (and whatever the iPhone connector is called) have a solar panel or thin battery on/in the back cover to trickle load the phone, an app whereby you can customize what is shown on the eInk screen. I think it has more potential as an accessory than a built-in solution.

Interestingly, E Ink Corp seemed to have been thinking along those lines later in the full-length video, which is over 30 minutes.

I like the idea of an e-ink screen that attaches to the phone as part of the cover. The newest version of e-ink, which looks like a laminated business card, is cardboard-thin anyway, so why not design it into a case you can activate through the micro-USB port or some other means? Make them for the most popular phones, which will probably be iterations of the Galaxy S and iClaudiusPhone.